lecture 3 Flashcards
1
Q
What is ‘Incidence’?
A
- The incidence of a disease is the rate at which new cases occur in a population during a specified period.
- e.g. the incidence of thyrotoxicosis during 1982 was 10/100 000/year in Barrow-in-Fumes compared with 49/100 000/year in Chester
2
Q
What is ‘Prevalence’?
A
- the prevalence of a disease is the proportion of a population that are cases at a point in time
- the prevalence of persistent wheeze in a large sample of British primary school children surveyed during 1985 was approximately 3%
- the symptom being define by response to a standard questionnaire completed by the children’s parents
- prevalence is an appropriate measure inly in such relatively stable conditions, and it is unsuitable for acute disorders
3
Q
What is a Risk Factor?
A
- something that increases your chances of getting a disease
- sometimes, this risk comes fromsomething you do
- e.g. smoking increases your chances of developing colon cancer
- therefore, smoking is a risk factor for colon cancer
- other times there’s nothing you can do about the risk, it just exists
- e.g. people 50 and older are more likely to develop colon cancer than people under 50
- age is arisk factor for colon cancer (in fact, it’s the number one risk factor)
4
Q
How is population health a diagnostic aid?
A
- defining disease (nosology)
- measuring diseases and conditions in populations was foundational to the emergence of modern medicine
- pluralist medicine regarded every individual’s sickness to be unique to that individual in personal circumstances, time and place (similar to complementary medicine)
- from early C19th, new mathematical methods were employed to compare cases and determine that different people were afflicted with the same disease
- first done with patients of tuberculosis
- vital statistics: ‘thermometer of health’, the bookkeeping of death
- Adolphe Qutelet (belgian, 1796 - 1874): began to look at ‘social physics’ or ‘social statistics’ = systematic disease patterns
- concept of the ‘average man’ who could be measured in large numbers and expressed mathematically – average mental, moral and physical characteristics
- disease detective
- why are THESE people sick NOW and in THIS PLACE?
5
Q
What is the epidemiologist asking?
A
• investigating where, when and who fell sick helps discover what was causing the disease; what the RISKs were
6
Q
Who is Dr John Snow?
A
- father of infectious disease epidemiology
* mapped cases of cholera in Soho London in 1854 and traced the source back to the water pump in Broad Street
7
Q
What are our population health questions on metabolic syndrome?
A
- problem: a chronic condition triggered by weight gain
- who has metabolic syndrome
- where do they live
- what are the characteristics of the people who develop it? age/sex/income/ethnicity/social status
- is there something significant about where they live? services/shops
- e.g. tracing obesity trends among U.S. adults: an epidemic
- spreads from the south, particular african americans and hispanic, poor areas
8
Q
What were the obesity stakes by country in 2009?
A
- US, Mexico, UK on top
- Japan, South Korea on the bottom
- can this be DNA? can you see patterns?
9
Q
Where are more adults obese?
A
- more adults are obese in more unequal rich countries
- greater amounts of income inequality lead to great levels of obesity
- obesity is a disease of poverty amidst affluence i.e. inequality - the embodiment of being a ‘loser’
10
Q
What is the effect of globalisation?
A
- destroys employment opportunities for both low and middle class
- not enough disposable income in america means economy may not recover
- high cost of housing in australia
- trickle down not good
11
Q
Can it just be changes in activity levels?
A
- lazy bums
- have they changed THAT much in just 40 years?
- new evidence not that children are doing less so they put on weight, but that becoming overweight causes them to do less
- many people who are overweight still work all day on their feet, lift weights, use their upper arms
- people perhaps walk less, but the decline in walking happened earlier
12
Q
What happened with the move to civilisation?
A
- decline in health
- decline in variety of diet - increased amount of carbs
- people got shorter
- lived in their own filth etc
- famine
- sicker with industrial age
- now public health means we live in an age where pathogenic diseases are not our biggest issue
13
Q
Or is it the food?
A
- human behaviour is not necessarily sufficient to explain the increase in obesity
- early 1970s: high food prices and falling farm incomes threatened the re-election of Richard Nixon
- Earl ‘Rusty’ Butz, US Secretary for Agriculture brokered free trade deal with Malaysia to export cheap, subsidised corn in return for Palm Oil
- US corn growers urged to plant corn from corner to corner
- subsidies destroyed Mexican corn farmers’ exports leading to desperate illegal immigration to US
- currently 200 million migrant workers in the world
- Sugar cane growers (especially Cuba) lost markets to high-fructose corn syrup HFCS55
- far sweeter than cane sugar
- Fast food industry able to cut costs of production of sweet drinks (coca cola, Pepsi), french fries and popcorn leading to a massive increase in affordability of fast food over real food
- now cheaper in US to buy a McDonald’s meal than a pear
- “Becoming obese,” says James Hill, an epidemiologist in the field of obesity, “is a normal response to the American environment”
14
Q
What is corn syrup?
A
- In use since 1975
- 7 times sweeter than Cane Sugar and therefore when Coca Cola and Pepsi changed from 50/50 HFCS/cane sugar to 100% HFCS, costs fell 20% → lower prices and bigger portions
- ALSO protected frozen food against freezer burn
- kept long-life products tastier
- in baking products (biscuits, buns, bread) → cheaper, tastier and seemingly ‘browned in the oven’
- RESULT: 80% of supermarket products contain HFCS55
- EXPLOSION of prepared foods, processed foods, frozen meals: cheaper, tastier, easier
15
Q
What is the problem with fructose?
A
- it bypasses the usual complex breaking down processes in the body and goes straight to the liver
- i.e. metabolic shunting
- not seen to be a problem at first, but now some argue that it produces insulin resistance quickly
- HFCS = huge increase in sugar load in body which is not broken down
- Hidden dangers: fruit juice with Children: one orange has its fructose dispersed with fibre
- a glass of fruit juice = SIX oranges, no fibre to break down the sugar and concentrated fructose
16
Q
What is palm oil?
A
- palm oil imported in deal on free trade
- mid 1970s new technologies made it a viable commercial fat: for frying french fries, margarine, bread, pies
- as dense and saturated as beef lard, more saturated than pig lard
- BUT cheap, ‘good in the mouth’ and above all STABLE – products did not biodegrade on the shelf and lasted longer
- neither did they biodegrade in the body
17
Q
What were the economic results?
A
- food prices fell dramatically and consumers had cheap, tasty, sweet and fatty food that they did not have to prepare themselves
- animal feed prices fell dramatically as cattle, pigs and chickens were moved to feed on mass produced subsidised corn
- high calories in animals not evolved to eat corn – hypergrowth (chickens matured weeks earlier, cattle grew so much flesh their legs cannot hold them up)
- high profits from food lead to monopolies controlling all food production from farm to supermarket leading to mass industrialised food production, high profitable, lead to factory farming or food lots
- dramatic ecological changes: new deadly salmonella; massed animals living in feedlots knee deep in manure leading to high antibiotic use leading to antibiotic resistance ALSO pollution of groundwater by concentrated animal waste
18
Q
What are changes in products?
A
- animals fatter but to their detriment
- average US hamburger can contain the homogenised flesh and fat of up to 300 different animals leading to huge increase in contamination and food poisoning (US ~80 million cases pa: ~5000 deaths pa; i.e. ~27% incidence pa; Aust: 42,000 cases pa)
19
Q
What changes have occurred in human diet and human shape?
A
- Food Inc: the changes to our food in industrialised economies in the last 40 years have been greater than since the rise of agriculture
- the metabolic syndrome epidemic has come from a profound change in the food provided for us by industry and which we find cheap, convenient and satisfying
- is it mass poisoning?
